Synthesis of alcohols, particularly methanol, by the catalytic reaction of synthesis gas (syngas) is a well established chemical process. The process may be carried out either in a liquid phase or in a vapor phase utilizing a catalyst. In this process carbon monoxide and hydrogen are catalytically reacted to form methanol. A particular catalyst to which the present invention is directed comprises, in its as-provided form, a mixture of metal oxides consisting essentially of copper oxide, zinc oxide and an oxide selected from the group consisting of alumina, silica and chromia. Such catalysts must be activated before use to bring them to a catalytically active state for use in the methanol synthesis process. This requires reduction of one or more metal oxides to a more active lower oxidation valence state. Typically, in the liquid phase methanol synthesis a slurry system is used wherein the catalyst is suspended in an oil slurry. The reduction is usually accomplished by contacting metal oxide catalyst in the slurry with hydrogen gas in a controlled manner which typically reduces the copper oxide in the catalyst to metallic copper while still retaining the remaining metals in their oxide form, i,e., zinc oxide, alumina, silica and/or titania.
The present invention is directed to a method for improving the catalytic activity of such catalyst after the reduction to activate the catalyst.
It is thus an object of the present invention to provide a method for improving the catalytic activity of an alcohol synthesis catalyst by a post-reduction treatment.
It is yet another object of the present invention to provide a method for improving the catalytic activity of an alcohol synthesis catalyst which may be conducted in situ in the same reactor in which the methanol synthesis takes place.
These and other objects of the invention will be apparent from the following description and from practice of the invention.